10 March 2017

Single vs Multi (fibre cable mode)


Kable Fibre Optik
- Cahaya lalu pada core.
- Clading akan kepung dan pastikan cahaya sampai ke hujungnya




Single Mode
- Jarak lebih jauh
- Laluan kecil, perlu sumber cahaya yg kuat, device transmisi agak mahal











Multi Mode
- jarak bawah 10 batu
- speed kurang sikit(aku pun confuse)
- harga device transmisi  kurang

11 January 2017

video codec

Ada 2 benda perlu difahami terlebih dahulu.
1- codec
2- video file format


Codec:
  algoritma(formula) yg digunakan utk compres(decompres) video. 

  • Jenis
    • MPEG-1
      • kebanyakkan VCD di kompress guna algoritma ni( *.dat file format)
    • MPEG-2
      • most DVD ( *.vob file format)
    • MPEG-4
    • DivX
    • XviD
    • X264

Video file format: 
   adalah bekas(container).

  • Jenis: 
    • mp4
      • contoh nama file: movie.mp4
    • avi (Audio Video Interleaved )
      • contoh nama file: movie.avi
    • wma
      • contoh nama file: movie.wma
    • mkv
      • contoh nama file: movie.mkv
    • Flash Video( flv dan swf)
      • contoh nama file: movie.flv   /  movie.swf
  • Fungsi utk bungkuskan audio, video dan codec dalam satu file
    #Satu file video mengandungi beberapa 'barang'. Antaranya adalah gambar, dan suara(audio).



Ada container yg boleh diisi dengan pelbagai jenis codec. Contoh: 
 - container : AVI
   - support codec:  MPEG-2, DivX, or XviD



Ada player/tv/dvd yg support container tertentu, namun tak ada semua codec.
Contoh, player A support container AVI, tapi hanya ada codec utk MPEG-2 dan DivX.
Player B pula support Container AVI, dan support semua codec.

Jadi bila ada satu file nama tuah.avi yg di kompress guna codec XviD, file ini hanya boleh dimainkan di player B sahaja, dan tidak di player A.

Untuk membolehkan tuah.avi dimainkan di player A, perlulah gunakan video converter(contoh AnyVideoConverter(http://avidemux.sourceforge.net/) atau avidemux(http://avidemux.sourceforge.net/)) utk create file baru yg dicompress guna codec XviD.




ref:
1- http://www.makeuseof.com/tag/all-you-need-to-know-about-video-codecs-containers-and-compression/
2- http://www.makeuseof.com/tag/an-introduction-to-codecs-converters-and-rippers/

18 October 2016

connect to wifi wpa2

This doc show how to connect to wpa2 essid using command line

DISABLE NETWORK_MANAGER dulu


 wpa_passphrase SSID PASSWORD > CONFIG_FILE
eg:
# wpa_passphrase myWifi mypassword > wpa.conf


 to list available driver
#      wpa_supplicant



# sudo wpa_supplicant -iwlan0 -c wpa.conf -Dwext
// -i  wireless card
// -c  config file
// -D  driver



ref: http://askubuntu.com/questions/16584/how-to-connect-and-disconnect-to-a-network-manually-in-terminal

15 October 2016

vlan Membership Flag

Here are the definitions that I pulled from page 126 of the User Guide:

T          --  The interface is a member of a VLAN. All packets forwarded by the interface are tagged. The packets contain VLAN information.
U          --  The interface is a VLAN member. Packets forwarded by the interface are untagged.
F          --  The interface is denied membership to a VLAN.
Blank    --  The interface is not a VLAN member. Packets associated with the interface are not forwarded.




ref:
http://en.community.dell.com/support-forums/network-switches/f/866/t/19495197

28 September 2016

download laju: aria

aria2c  -c -s 16 -x 16 http://10.0.7.10/buf/HDP_2.5_vmware.ova

c: continue
s: split connection
x: max con per server

21 September 2016

Isu screen 'screen.xterm-256color'

Sejak update LTS 16, ada masalah utk run screen pada remote server.
Error:
 Cannot find terminfo entry for 'screen.xterm-256color'


Penyelesaian:
Sebelum run screen, run command di bawah pada remote server.
  export TERM=xterm-256color




FREEBSD
   setenv NNTPSERVER news.someisp.com

08 September 2016

Android DNS


Display dns use by android:
-getprop net.dns1
-getprop net.dns2


Set dns to use by android
-setprop net.dns1 113.113.113.113